ISP AOL has dumped Microsoft's e-mail identification technology, Sender ID, although it does intend to stick with the Sender Policy Framework (SPF) element:

"Given recent concerns expressed by the Internet Engineering Task Force (IETF), coupled with the tepid support for Sender ID in the open source community, AOL has decided to move forward with SPF," Nicholas Graham, AOL spokesperson, told http://internetnews.com via e-mail.

Despite the bombshell decision, the world's top ISP isn't completely severing its ties to Sender ID: The company still will publish Sender ID files so its users' e-mails are compliant with Sender ID-enabled servers and applications. But it's enough of a vote of no confidence in Microsoft's e-mail authentication strategy to warrant concern for Sender ID proponents.

The Redmond giant has been steadfast in its refusal to disclose specifics on patents surrounding the Sender ID technology, saying only that the claims involve Sender ID and the Purported Responsible Address (PRA) algorithm used in conjunction with it. Microsoft also is requiring Sender ID implementers to sign a license agreement to protect those unspecified patents, the terms of which have the open source community up in arms.

To cut a long story short, nobody likes the idea if giving a corporate bigwig too much control over something that could easily become an important foundation of e-mail systems.

There were also a couple of technical problems for AOL, such as concerns over backwards compatibility with SPF.

Either way, it's a pity Microsoft couldn't have been more flexible as it has the power to push such technology far better than most. A win for SPAM?